Planning your garden in Ottawa’s unpredictable weather can be difficult, especially for novice gardeners. Fortunately, I’ve gathered up some local knowledge from Ottawa residents who’ve “been there, grown that,” and are ready to share their wisdom with you.
Ottawa is in what the USDA calls “Zone 5” in its 9+ zone guidelines, which account for general temperature and humidity changes that will impact how specific varieties of plants will grow in your area. With this in mind, there are a good variety of perennials (grow back year after year and go dormant in the winter) and annuals (live one life cycle and die in the fall/winter) that do very well in our climate.
Here are 5 Perennials which will thrive in your Ottawa garden so that you can be the envy of the neighbourhood! To make things truly foolproof, scroll down and you can download full care instructions for each one. Happy gardening!
There are over 6,000 different varieties of ornamental grasses available that range in colour, variegation, height, and spread. They are a fantastic way to add height, texture, and movement to your garden.
DESCRIPTION: Grasses and inflorescences (flower tassels and plumes) can vary in colour, size, shape, and height
FULLY MATURED SIZE: From ankle height to over 6 feet in height
DOES BEST IN: Not overly picky about soil types
- Ornamental grass varieties are divided into “clumpers” or “runners”, meaning the former will spread much less than the latter
- Known for their hardiness and resilience
- Highly beneficial to the surrounding ecosystem by providing a habitat for wildlife and prevent soil erosion
- Grows best in partial to full sun
- Happy in just standard gardening soil. Not overly picky!
- Low maintenance once established
- No pruning required
- Add privacy to your space
*it is important to note that there are quite a few invasive grasses that will quite literally take over your garden if you are not vigilant in your garden care. Avoid grasses like Giant Reed, Skinner’s Gold, Lime Grass, Manna Grass, Giant Silver Grass, Ribbon Grass, and Cord Grass, to name a few.
Hostas are beloved of many gardeners, because they are considered “easy” plants. Hostas actually come in a great number of varieties, and the majority of them grow very happily in Zone 5 weather.
- Come in a massive variety of sizes, colours, and verigations
- Drought tolerant
- Important shade garden staple
- Low maintenance
- Great for full shade to partial shade gardens
- Fully matured (4-8 years once planted), Hostas can grow to 12” in height to 50” and spread up to 60”+ in width
- Some Hostas bloom!
- Hostas grow best in well balanced, loose, well draining soil
- Keep your Hosta moist, but not wet
- Hostas LOVE to be fertalized
- Watch out for slugs and other pests!
If you are unsure as to whether you like Hostas, I recommend visiting Artistic Landscape Design, as they have the best variety of Hostas in Ottawa.
Ground covers, like Creeping Flox and Creeping Thyme, are a great way to fill portions of your garden, keep your soil warm and protect the roots of other plants around it. They are also a fantastic way to reduce weeds and create more of an English Garden aesthetic.
DESCRIPTION: Spring blooms are fragrant and star-shaped in pastel colours. Foliage consists of stems with needle-like evergreen leaves.
FULLY MATURED SIZE: 6” height X 2’ spread
DOES BEST IN: Rich, moist, well draining soil
SUN: Full sun
BLOOMING TIME: Spring (3-4 weeks mid to late spring)
COLOURS: Pink, red, white, blue, rose, lavender, purple
- Can be planted in gardens, in between pavers, or in a planter.
- Cut down your Creeping Phlox over time to encourage regrowth of softer foliage and second bloom
- Easy to care for
- When planting, pay close attention to the planting and spread instructions
- Thrives in a variety of conditions
- Must be watered frequently during the heat of summer
- Considered the most colourful ground cover option
- Deer resistant
DESCRIPTION: Tiny, fuzzy oval leaves with blooms of similar size
FULLY MATURED SIZE: 3” height X 12” spread
DOES BEST IN: Balanced, well draining soil
SUN: Full to partial sun (minimum of 4 hours direct sun/day)
BLOOMING TIME: Late spring to early summer
COLOURS: Purple, red, pink
- Tolerant of poor soil conditions and drought
- Pest and disease free
- Relative to traditional Thyme
- Grows quickly
- Tolerates foot traffic well (great option for in between pavers or patio stones)
- Not usually harvested, but English Creeping Thyme is edible and can be made into teas and medicines.
- Deer and rabbit resistant
- Bee friendly!
- Beautiful fragrance
- Prevents weed growth when fully established
- Comes in many varieties, such as Red Creeping Thyme, Purple Carpet, Spicy Orange, and Woolly Thyme to name a few.
Some other ground covers to grow in Ottawa are Stonecrop, Violets, and Dianthus.
*Lily of the Valley is a beautiful ground cover but is toxic to pets and wild animals.
Used throughout history as a medicinal herb, Echinacea has been a staple in many gardens for years. If you are planting a pollinator garden (or even planter!), Coneflower is an essential addition.
DESCRIPTION: Dark green foliage, raised cone center filled with seeds, blue/violet petals
FULLY MATURED SIZE: 20-48” X up to 48” spread
DOES BEST IN: Average, well draining soil (tolerant of poor soil conditions)
SUN: full sun
BLOOMING TIME: mid-summer in to the fall (usually late June to August, depending on weather)
COLOURS: blue/violet (other coneflower varieties come in a multitude of colours)
- Low maintenance
- Drought resistant
- Can take Zone 5 extreme heat & humidity
- Tolerant of poor soil conditions
- Attracts pollinators!
- Deer resistant
- Susceptible to very few viruses
There are countless bulb options to choose from that thrive in Zone 5. They give your garden stunning colour and foliage all spring and summer long. Blubs are also a great way to get a head start on your spring garden and are so much fun to watch grow and bloom!
- Choose from a huge variety of flowers, heights, blooming times, and sun requirements
- The most hardy bulbs for Zone 5 include Daffodil, Iris, Tulip, Lily, Snowdrop, Hyacinth, and Crocus
- Bulbs are divided into spring and summer blooming bulbs
- Spring blooming bulbs must be planted the previous fall with enough time before the ground freezes (ideally 6-8 weeks)
- Summer blooming bulbs are planted in the spring (summer bulbs will not live through our winter, so they must be dug up and stored inside through the winter months and replanted in May-June)
- Plant in a good drainage area
- Make sure to thoroughly read the planting depth and instructions for the best result
For early spring bloom, choose Crocus and snowdrops. For late spring and in to the summer months, choose bulbs like Iris, Tulips (an Ottawa staple and come in a wide variety of colours), Daffodils, Lilies, Hyacinth, Narcissus, Allium (Ornamental Garlic) (and my personal favourite because they look like something out of a Dr. Seuss book!).
If you were curious about how Zoning works, check out this link from Natural Resources Canada to learn more about plant hardiness across Canada.
I hope you and your loved ones are well and that you have been able to enjoy some of the sunshine and get out in the garden!